JP2587440B2 - Method for producing p-substituted o-benzylphenol - Google Patents

Description

The present invention relates to a method for producing p-substituted o-benzylphenol by reacting the p-substituted phenol with a benzylating agent at an elevated temperature in the presence of a condensing agent.

It is known that mixtures of various proportions of 2-benzylphenol, 4-benzylphenol and 2,6-dibenzylphenol are always obtained by benzylation of phenol. That is, when p-cresol is condensed with benzyl alcohol in the presence of aluminum chloride as a catalyst, the dibenzylated product is converted to 30
The formation of a product mixture containing about 36% by weight is described, for example, in J. Am. Soc., 53 , 2379 (1.
931).

Further, benzyl chloride and a condensation catalyst such as FeCl ₃ , FeSO ₄ or Z
NSO ₄ dibenzyl click Rolf enol When benzylated 4 click Rolf enol using is also known that to produce up to 18 mole% [Abudeyurasureba (Abdurasule
va)] et al., Zh. Org. Khim, 9 , 132 (197
3). Further Chiekosurobakiya Patent No. 170,972 [Chemical Abstracts (Chemical Abstracts), 89, 61096
(1978)] is 2-benzyl-4-chloride in which 4-chlorophenol is condensed with benzyl chloride at a molar ratio of 4: 1 in the presence of a sulfonated styrene / divinylbenzene copolymer (= strongly acidic cation exchanger). Describes a method for producing phenol. Although the yield of the desired product is 83% based on the reacted 4-chlorophenol, relatively high amounts of high boiling products are formed. The ratio of 2-benzyl-4-chlorophenol to high boiling product is 4.16: 1.

Known processes for the preparation of p-substituted o-benzylphenols produce large amounts of dibenzylated products and / or high-boiling by-products, resulting in lower yields of the desired p-substituted o-benzylphenol. That is a disadvantage. The known processes are therefore largely unsuitable for the industrial production of p-substituted o-benzylphenols.

Now, when a p-substituted phenol is reacted with a conventional benzylating agent in the presence of a specified zeolite of the type of faujasite, without the formation of undesirable by-products,
-It has been found that the desired monobenzylation of substituted phenols can be achieved.

Therefore, the present invention specifies a condensing agent to be used in producing a p-substituted o-benzylphenol by reacting the p-substituted phenol with a conventional benzylating agent at an elevated temperature in the presence of a condensing agent. The present invention also relates to a method for producing p-substituted o-bensilphenol, which is a synthetic zeolite of the faujasite type.

The p-substituted o-benzylphenol obtained according to the present invention has the formula Wherein R ¹ represents halogen, C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy or C ₁ -C ₁₂ alkyl mercapto, and R ² represents hydrogen, halogen, cyano group, C ₁ -C ₄ alkyl it can be described by, or an carbo -C ₁ -C ₄ alkoxy group.

P- which can be used as a starting material in the process of the invention
Substituted phenols have the formula [Wherein R ¹ has the meaning described above].

The benzylating agent has the formula Wherein R ² has the meaning described above, and R ³ is halogen,
A hydroxyl group, C ₁ -C ₄ alkoxy, aralkoxy or aryloxy].

Suitable alkyl groups in the alkoxy and alkylmercapto groups mentioned for R ¹ and for R ¹ have ¹ to 12, preferably 1 to 4 carbon atoms. Examples which may be mentioned are methyl, ethyl, n-propyl, isopropyl, n
-Butyl, isobutyl, sec-butyl, tert-butyl,
Pentyl, hexyl, octyl, decyl and dodecyl,
Preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-
Butyl, particularly preferably methyl, halogens which may be mentioned are fluorine, chlorine, bromine and iodine,
Preferably chlorine and bromine, particularly preferably chlorine.

Examples of carbo-C ₁ -C ₄ alkoxy that may be mentioned are carbomethoxy, carboethoxy, carbopropoxy and carbobutoxy groups, preferably carbomethoxy and carboethoxy groups.

Aralkoxy groups which may be mentioned are those in which the alkyl part has 1 to 4 carbon atoms and the aryl part has 6 to 12 carbon atoms, for example 2-phenylethoxy, especially benzyloxy groups.

Aryloxy groups which may be suitably mentioned are optionally substituted phenoxy groups, for example phenoxy, toloxy and 4-chlorophenoxy groups.

The following p-substituted phenols such as p-chlorophenol, p-cresol, hydroquinone monoethyl ether, p-hydroxythiophenol, p-bromophenol and p-fluorophenol, preferably p-chlorophenol, p-cresol and hydroquinone Monomethyl ethers, particularly preferably p-chlorophenol and p-cresol, can be used in the process according to the invention.

Benzyl agents of the formula (II) which may be mentioned by way of example are benzyl chloride, benzyl alcohol, dibenzyl ether and p-chlorophenyl benzyl ether, preferably benzyl alcohol, dibenzyl ether and p-
Chlorphenyl benzyl ether.

According to the invention, the phenol and benzylating agent are generally present in a molar ratio of from about 10: 1 to 0.1: 1 (phenol: benzylating agent), preferably from 6: 1 to 0.2: 1, particularly preferably from 5.1: 1 to 1.0: 1. Used in the ratio.

Synthetic zeolites of the faujasite type which can be used as a condensing agent in the present invention are known, for example, DWbrek (Br
eck), Zeolite Molecule sieve (Zeolite M)
elecular Sieves), John Wiley and Sons Inc., New York, 1974
Also described in Peter A. Jacobs, Carbonionogenic Activity of Zeolites, Elsevier, Amsterdam, 1977.
In the method of the present invention, zeolite X and zeolite Y are particularly preferred as the synthetic zeolite of the faujasite type.

The synthetic zeolite of the faujasite type used in the method of the present invention has a general composition formula (1.0 + 0.2) M _{2 ]} nOAl ₂ O ₃ (2-6) SiO ₂ ZH ₂ O, wherein M is Represents sodium, potassium, cesium, calcium, tin or hydrogen ions, n is its valence, and Z is the number of water molecules].

Zeolite X is a name for synthetic Fuoujiyasaito having SiO ₂ / Al ₂ O ₃ ratio of 2-3, also zeolite Y
Is the name for synthetic Fuoujiyasaito having SiO ₂ / Al ₂ O ₃ ratio of 3-6.

The amount of the synthetic zeolite of the faujasite type used according to the invention is generally about 1 to the phenol used.
5050% by weight, preferably 5-40% by weight.

The reaction is carried out in a temperature range of about 100-250 ° C, preferably 125-220 ° C, particularly preferably 150-200 ° C.

The process according to the invention is generally carried out at atmospheric pressure. However, it may be under elevated or reduced pressure, for example from 0.1 to 30 bar, preferably from 1 to 10 bar, particularly preferably from 1 to 5 bar.
It may be done in a bar.

Generally, the reaction time according to the method of the present invention is about 10 minutes to 50 hours, preferably 30 minutes to 30 hours. However, the reaction time depends essentially on the activity and amount of zeolite used.

The reaction according to the invention can be carried out in a continuous or batch mode.

When the reaction is completed, the reaction mixture, if appropriate after removing the condensing agent, can be worked up in a conventional manner by vacuum distillation.

The mixture comprising phenol, benzylating agent and a small amount of the desired product obtained in the first fraction during this distillation can be reused in the reaction after adding the phenol and fresh benzylating agent.

According to the invention, o-benzylphenol is obtained in high purity and in a yield of more than 90% of the theoretical amount based on the reacted phenol.

The process according to the invention can be carried out, for example, as follows: The molten phenol, the condensing agent and the benzylating agent are introduced into an apparatus equipped with a stirrer and a reflux condenser, and the reaction mixture is then brought to the appropriate reaction temperature. Bring. However, it is also possible to add the benzylating agent to the mixture of phenol and zeolite after the reaction temperature has been reached. The reaction is kept at the specified reaction temperature until the benzylating agent has reacted as completely as possible. After removing the catalyst by filtration, the reaction mixture is distilled under vacuum to give the p-substituted o-benzylphenol in high purity. Furthermore, it is also possible to carry out the vacuum distillation directly after the completion of the reaction, ie without removing the catalyst in advance. In a continuous process, the reaction may conveniently be carried out in a fixed bed reactor. In this case, the feed rate (LHSV = amount of starting mixture / amount of catalyst × h) depends on the phenol and benzylation fed at a constant rate by a stream of inert gas (nitrogen, noble gas and / or steam) through the preheating section. 0.5 to 5 hours ^-1 for the mixture of agents. The reaction mixture emerging from the reactor is fed to a distillation column following the condensation reaction.

The advantage of the method of the present invention over the conventional method is that the p-substituted o
High yield of benzylphenol, high conversion of phenol and low formation of high-boiling by-products such as dibenzylphenol and other polynuclear aromatics.

p-Substituted o-benzylphenols are disclosed in British Patent 1,330,
No. 753 and U.S. Pat.
Used as antioxidant and bactericide.

 The following examples illustrate the method of the present invention.

Example 1 68.2 g (0.5 mol) of 4-chlorophenol was reacted with 10.8 g (0.1 mol) of benzyl alcohol at 200 ° C. in the presence of 6.0 g of Na-Y type zeolite. After removing the catalyst,
76.2 g of crude product were obtained, the composition of which was determined by gas chromatography: 71.2% of 4-chlorophenol, 25.4% of 2-benzyl-4-chlorophenol, 0.3% of o-benzylphenol, 1.3% of dibenzyl ether and 1.3% of high. 1.8% of the boiling product (2,6-dibenzyl-4-chlorophenol). The crude product was distilled off in a conventional manner under vacuum. The first fraction is 2
A small proportion (<1%) of benzyl-4-chlorophenol
54.7% of unreacted chlorphenol contained in the above. The main fraction from the distillation contained 20.8 g of 2-benzyl-4-chlorophenol (yield 94.8% based on 4-chlorophenol used) and the rest comprised high-boiling oils.

The following abbreviations are used in the following: Z zeolite CP 4-chlorophenol BCP 2-benzyl-4-chlorophenol HB high-boiling product = 2,6-dibenzyl-4-chloro-
Or -4-methyl-phenol and polynuclear aromatic BA benzyl alcohol BP o-benzylphenol DBE dibenzyl ether CPBE 4-chlorophenyl benzyl ether PC p-cresol BPC 2-benzyl-p-cresol The rest are DBE, CPBE, BA , PCBE and o-benzylphenol.

Examples 2 to 7 Table 1 shows CP and BA determined by gas chromatography.
As a function of zeolite using the composition of the reaction mixture of The molar ratio of CP: BA was 1: 1. For this purpose,
6.5 g of CP and 5.4 g of BA were heated together with 3.0 g of Z at 200 ° C. for 3 hours.

The above table shows that the reaction proceeds with high selectivity when the faujasite type zeolite is used.

That is, the formation of high molecular weight by-products is substantially suppressed even at unfavorable CP: BA molar ratios, such as 1: 1, which is particularly economical since these by-products must generally be discarded. Furthermore, Y zeolites and in this case especially
It is clear that the Na-Y zeolite gives the best results with regard to the conversion of this reaction and the suppression of high-boiling by-products.

Examples 8-12 CP and BA at various molar ratios over Na-Y zeolite at 200 ° C
Condensed down for 3 hours. Table 3 shows the composition of the reaction mixture as determined by gas chromatography.

In the above reaction, 1.5 g of Na-Y zeolite was used. The total amount of CP and BA was 150 mmol.

Excessive CP reduces the formation of high boiling products since multiple condensations of BCP already formed with benzyl alcohol can be largely avoided in the process. That is, the BCP of 4.16 described in Chieko Slovak Patent 170,972.
/ HB ratio is more than twice at 4: 1 CP: BA molar ratio and 2 CP / BA
A BCP / HB ratio of 7.4 is obtained with the process of the invention even at BA molar ratio.

Examples 13-15 6.5 g of CP and 5.4 g of BA were brought to the temperature specified in Table 4 and then 3.0 g of Na-Y zeolite was added to the mixture. Table 3 shows the composition of the reaction mixture after 3 hours of reaction time as determined by gas chromatography.

Table 3 shows that the reaction proceeds reasonably quickly even at 150 ° C. In the selected temperature range, only slight changes in the BCP: HB ratio were observed at different temperatures, and similar conversions were achieved.

Examples 16-17 At 200 DEG C. for 3 hours with 6.5 g of CP and 3.0 g of Na-Y zeolite of the benzylating agent in the specified molar ratio. Table 4 shows the composition of the reaction mixture as determined by gas chromatography.

DPBE and CPBE were removed as by-products in the first fraction of the distillation purification of the reaction mixture. As Table 4 shows, these by-products can be converted to BCP by the addition of CP.

Examples 18 and 19 PC and BA were mixed in a 4: 1 molar ratio and heated to 200 ° C. for several hours with fujasite-type zeolite (20 g / PC mole). Table 5 shows the reaction time and the composition of the reaction mixture as determined by gas chromatography.

Table 5 shows that the use of faujasite zeolite gives good conversion and excellent selectivity even in the benzylation of PC. The yield based on the reacted PC was 94%.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C07C 43/23 C07C 43/23 67/343 67/343 69/92 69/92 255/53 255 / 53 323/20 323/20 // C07B 61/00 300 C07B 61/00 300 (72) Inventor Rotar Puppe, Germany Day 5903 Bruciait Ambier 10a (56) References Chemistry Letter, (1983), P. 1101-1104

Claims (5)

(57) [Claims] In preparing a p-substituted o-benzylphenol by reacting the p-substituted phenol with a conventional benzylating agent at an elevated temperature in the presence of a condensing agent, the reaction is carried out at 100-250 ° C. Performed at a temperature and the condensing agent used has a general composition formula (1.0 + 0.2) M _{2 ]} nO Al ₂ O ₃ (2-6) SiO ₂ ZH ₂ O, wherein M is sodium, potassium, cesium, calcium, A tin or hydrogen ion, n is a valence thereof, and Z is a number of water molecules.] A synthetic zeolite of the foujasite type represented by the following formula: Manufacturing method. 2. A process according to claim 1, wherein the synthetic zeolite of the faujasite type used is zeolite X and / or zeolite Y. 3. The process as claimed in claim 1, wherein the amount of the synthetic zeolite of the faujasite type used is from 1 to 50% by weight, based on the phenol used. 4. The process according to claim 1, wherein the amount of the synthetic zeolite of the faujasite type used is 5 to 40% by weight, based on the phenol used. 5. A p-substituted o-benzylphenol is represented by the formula Wherein R ¹ represents halogen, C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy or C ₁ -C ₁₂ alkyl mercapto, and R ² represents hydrogen, halogen, cyano group, C ₁ -C ₄ alkyl Or a carbo-C ₁ -C ₄ alkoxy group], and these p-substituted phenols of formula (I) have the formula Wherein R ¹ has the meaning described above. Wherein R ² has the meaning given above and R ³ represents halogen, hydroxyl, C ₁ -C ₄ alkoxy, aralkoxy or aryloxy. A method according to any of the preceding claims.